I scored the same, for the same reason. What I find interesting is that the Helvetica logos are a lot nicer in my opinion even though the difference is subtle. Having things parallel to the baseline improves the look dramatically over the angled bits in Arial.

Same score. I also applied the same heuristic. I wonder what I should have looked for in the MATTEL one.

It's very subtle and more pronounced in the other logos shown, but the horizontal line in the "A" is closer to the baseline in Helvetica than in Arial.

This probably is more to do with recreating the logo imperfectly than the font itself but the kernning was way off on the Arial version.

Exactly what I used for reference to decide as well (got 20/20).

18/20, they're fairly easy to tell apart, except for MATTEL and TOYOTA which are quite subtle (and I got wrong precisely because I couldn't remember which is which). Both the capital and lowercase R are a dead giveaway.

MATTEL and TOYOTA are the most difficult ones IMO. I got Toyota right because the non-circular O's in the Arial variant just look wrong to me.

The Y is also slightly different too.

TOYOTA was completely impossible to me. I had AGFA wrong because I'd forgotten which had which G. I got lucky on MATTEL. The others are easy once you know that Helvetica loves its horizontal lines.

Those are the two I got wrong as well. I had problems with capital R myself though.

Same. I wasn't sure what to look for with those particular capital letters.

Those are the two that stumped me, too

The tell for Mattel is the Arial 'E' has a shorter middle bar, whereas Helvetica has all equal length bars.

1/20 I guess I was able to tell them apart too?

Ha, in all but one (Mattel?) you pointed to Arial as being Helvetica. Just invert your heuristic! :-)

Indeed:

A = Angled = Arial

H = Horizontal = Helvetica

Some of the capitals (C, S) have that, too.

Similarly, lowercase r ends vertically in Helvetica, slanted in Arial.

I also got all except Mattel, despite not really using either typeface all that much. Lowercase 't' was also a dead giveaway in a lot of cases. I also noticed that the Helvetica answers seemed to have a slightly heavier weight, which really helped for the all-caps examples.

Ultimately, the Helvetica versions "felt right", and that probably contributed to my lucky guesses. A more challenging test would be to compare samples not associated with well-known brands.

19/20, yeah, the tricky ones are the capitals.